Khloé and Tristan began dating in September 2016, before it was reported in September that the couple were expecting their first child together. Tristan also shares a 1-year-old son, Prince Oliver, with his ex-girlfriend.

“This is something Khloé has wanted for years and years and yet it’s more than that: she didn’t want it unless she was in the right relationship for it," a source told PEOPLE. "She never let it happen with Lamar, intentionally, and she never considered it with James or French or anyone else she has seen."

“But this is such a wonderful moment for her: not only is she going to be a mother, she is going to be raising a child with a man she truly loves,” the source added. “Everyone is over the moon for them both.”